ABSTRACT
Theory for the combined bending and shear behaviour of multi-layer rubber-steel bonded blocks, used for estimating the lateral stiffness and critical axial load, was developed by Gent (1964) and is widely disseminated in the literature; the key equations from it also appear in most Standards for structural bearings. This theory is usually restricted to nominally small strain linear behaviour, and moderately high shape factor multilayer blocks, and the effect of axial compliance is not usually addressed. The material model used for the rubber is very simple, requiring only linear behaviour in simple shear and the approximation of incompressibility.
This paper describes the behaviour of rubber blocks that are unlike such customary laminated bearings in that (1) the number of layers is small, including the possibility of only one (2) the shape factor, and hence axial stiffness, is low (3) effects of kinematic nonlinearity and axial compliance are included. The work builds on an earlier experimental and FEA study, which addressed effects of non-linear lateral load-deflection behaviour and instability of single layer rubber blocks. More comprehensive experiments are reported and interpreted using an approximate analytical beam-column theory.
